Moonstone
Feldspar group, Orthoclase var. Moonstone · Semi-Precious Gemstone
Crystal System
Monoclinic system, typically forming prismatic or tabular crystals, massive or in beads
Mineral Group
Silicates - Tectosilicates (Feldspar group)
Chemical Formula
(K,Na)AlSi3O8
Formation Process
Igneous and pegmatitic formation, crystallizing from cooling magma as well as in hydrothermal veins and metamorphic rocks
About This Crystal
The specimen consists of polished spherical beads displaying a characteristic milky-white to pale translucent body color with a soft, glowing, pearly luster and visible adularescence
Physical Characteristics
White to milky body color with a white streak, exhibiting two directions of good cleavage at nearly 90 degrees, uneven to conchoidal fracture, specific gravity of approximately 2.56 to 2.58, and a brittle tenacity
Optical Properties
Biaxial negative optical character, refractive index ranging from 1.518 to 1.526, displaying pronounced adularescence (a billowy, moonlight-like sheen caused by light scattering between microscopic alternating layers of orthoclase and albite)
Hardness & Durability
Origin Region
Sri Lanka, India, Madagascar, Myanmar, Australia, and the United States
Hardness & Durability
Mohs hardness of 6 to 6.5, moderate toughness but vulnerable to hard knocks due to distinct cleavage planes, requiring some care when worn in daily jewelry
Care & Maintenance
Clean with warm soapy water using a soft brush; avoid harsh chemicals, ultrasonic cleaners, and steam cleaning; store separately from harder gems to prevent scratching
Rarity & Value
Common to uncommon depending on the quality of adularescence and transparency; high-value stones show strong blue sheen on a transparent background; typically untreated
Special Characteristics
Displays adularescence (schiller effect) which creates a floating light phenomenon resembling moonlight trapped within the stone
Lore & History
Historically associated with lunar deities in ancient Roman and Greek civilizations, revered as a stone of intuition, inner growth, and emotional balance, frequently linked to the Third Eye and Crown chakras in modern crystal healing traditions